#include <bits/stdc++.h>
using namespace std;
#ifdef tabr
#include "library/debug.cpp"
#else
#define debug(...)
#endif
int pref[100010][9];
void init(string a, string b) {
int n = (int) a.size();
for (int i = 0; i < n; i++) {
for (int j = 0; j < 9; j++) {
pref[i + 1][j] = pref[i][j];
}
int x = (a[i] == 'A' ? 0 : (a[i] == 'C' ? 1 : 2));
int y = (b[i] == 'A' ? 0 : (b[i] == 'C' ? 1 : 2));
pref[i + 1][3 * x + y]++;
}
}
int get_distance(int x, int y) {
int ac = pref[y + 1][1] - pref[x][1];
int at = pref[y + 1][2] - pref[x][2];
int ca = pref[y + 1][3] - pref[x][3];
int ct = pref[y + 1][5] - pref[x][5];
int ta = pref[y + 1][6] - pref[x][6];
int tc = pref[y + 1][7] - pref[x][7];
int res = 0;
int z = min(ac, ca);
res += z;
ac -= z;
ca -= z;
z = min(ct, tc);
res += z;
ct -= z;
tc -= z;
z = min(ta, at);
res += z;
ta -= z;
at -= z;
if (ac != ct || ct != ta || ta != ac || at != tc || tc != ca || ca != at) {
return -1;
}
res += max({ac, at, ca, ct, ta, tc}) * 2;
return res;
}
#ifdef tabr
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
init("ATACAT", "ACTATA");
debug(get_distance(1, 3));
return 0;
}
#endif
